This invention relates to a device for measuring forces and moments applied to a wheel axle for analyzing suspension and operating characteristics of a vehicle. In particular, the present invention relates to but is not limited to, a motorcycle force transducer device that is used for designing motorcycles or controlling motorcycle tests based upon measurements of dynamic forces and moments for improving ride and handling.
During operation of a two wheeled vehicle, such as a motorcycle, various forces and moments are imparted to the suspension system or chassis. Measurement of these forces and moments is useful for designing and evaluating performance of such vehicles. For example, axial forces F.sub.x, F.sub.y and F.sub.z and roll M.sub.x and steer M.sub.z moments are useful for evaluating performance and handling of two wheel vehicles such as motorcycles during cornering maneuvering, braking and acceleration events to evaluate stress and strain on various chassis locations.
To measure actual operating forces and moments, a vehicle can be adapted with "on-board" measurement equipment which measures operating forces and moments on the suspension system or chassis as an operator drives the vehicle over various terrain and conditions, or alternatively operating conditions can be simulated in a laboratory. In such application, measurement equipment is integrated with the suspension system or frame to measure and analyze loads to the suspension or chassis of the vehicle.
Prior measurement was incorporated into the rotating wheel axle of a two wheeled vehicle or into the vehicle suspension. For example, strain gauges have been incorporated into an inner bore of a wheel axle supported between suspension rods for force measurement. Use of a wheel axle having an inner bore reduces the strength of the wheel axle. Additionally, incorporation of measurement equipment into a rotating wheel axle requires the use of slip rings or other devices for measurement and requires a complex transformation from a rotating wheel coordinate system to a fixed vehicle coordinate system. Incorporation of measurement equipment into the suspension can provide large cross-coupling and complications due to suspension geometry.